To Find Giant Exoplanets Look For Debris Disks

A few thousand black holes have been discovered in the Milky Way so far, but there are billions more still left to find. Spotting exoplanets is not easy but researchers might have just found a shortcut to finding very large planets.

According to a paper in the Astronomical Journal, the presence of giant planets far from their host stars is signaled by a large debris disk. The researchers have shown that young systems with debris disks are more likely to have planets weighing more than five Jupiters. The planets’ gravity might be helping to keep the material stable.

“Our research is important for how future missions will plan which stars to observe,” lead author Dr Tiffany Meshkat, from Caltech, said in a statement. “Many planets that have been found through direct imaging have been in systems that had debris disks, and now we know the dust could be indicators of undiscovered worlds.”

The team focused on young stars between a few million and 1 billion years old. The researchers compared 130 single-star systems with debris disks that were detected by NASA’s infrared telescope, Spitzer, with 277 single stars that don’t appear to host any disk. Out of the 130, 100 have exoplanets, a fraction over 76 percent.

The remaining 30 didn’t have any known exoplanets, so the researchers ran a follow-up observation campaign just to make sure none had been missed.

They didn’t find any new planets but collected more data about debris disks. And that data is going to be important as there are many questions still in need of an answer. What role do these giant planets play in keeping the debris disk stable? And will smaller planets emerge from these disks? This study can’t answer that yet.

“It’s possible we don’t find small planets in these systems because, early on, these massive bodies destroyed the building blocks of rocky planets, sending them smashing into each other at high speeds instead of gently combining,” co-author Professor Dimitri Mawet, also from Caltech, added.

The evolution of planetary systems is, for the most part, still a mystery. We know that planets, especially gas giants, move around, shaping how the smaller objects interact but we lack a complete understanding of all the possible outcomes. What do you need to make a Solar System like our one?

More clues will hopefully come from upcoming missions like the James Webb Space Telescope and planet-hunting observatories like TESS that will be able to see better than our current tech. This research, however, tells us that debris disks are a good place to start looking for planets.